Arnie Coro, CO2KK
Hi amigos radioaficionados around the world, and in space at this moment…welcome to the weekend edition of your favorite radio hobby rogram, the one and only covering the more than 83 different ways that yu and I enjoy playing with our radios… From the Canadian AM broadcast and Dxer trying to set a new record of stations heard on a very small ortable radio, to the Cuban newcomer to amateur radio that yesterday visited me to return the 2 meters band MOXON rectangle antenna that I snt to him so that he could go on the air the very same day that he ceived his amateur radio license… Si amigos, yes my friends, you can besure that people do enjoy this hobby a lot, and even when the going gets difficult, like the day our small fishing vessel that was taking us to the CO4 Dx expedition of 1965 ran aground and water started to come into the hull, instead of panicking, we simply used our ham radio equipment to call for help, as at that time we had no VHF Marine radio coverage in that area of the Cuban archipelago.
Radio brings in so many nice moments, that recalling some of them while spending a nice afternoon at our radio club becomes part of our lives… Now let me give you a nice example of how radio has help a lot of persons to live a better life. For people with poor vision or that are totally blind, amateur radio is a great hobby that makes possible for them to meet friends, participate in contests and share with others their ham radio experience… For highly qualified engineers and telecommunications technicians , the radio hobby makes possible to perform some very interesting experiments using the amateur band frequencies… some of those experiments have become classics, like the ones made by a group of retired professional
Radio broadcast engineers that fully documented the dramatic improvement in performance for vertical antenna systems provided by elevated radials… Amateur radio operators have even made some very important discoveries in the area of radio wave propagation, and experiments that were done by amateurs demonstrated the existence of what we now know as Trans Equatorial Scatter Ionospheric Propagation, or just TEP for short, a fascinating communications mode that so far has defied theoreticians …
Here is now one of the most popular sections of the program… The antenna topics segment, that today will be devoted to part II of low cost broadband antenna systems. During the mid week edition of the show, I gave a lot of information about the FAN DIPOLE, and of its three most popular versions, the one designed for coverage of the 3 to 10 megaHertz part of the short wave spectrum, the one for 6 to 18 megaHertz, certainly the most popular design according to your e-mail messages and letters, and the small compact FAN DIPOLE that works nicely from approximately 13 to 39 megaHertz. At the present moment, and as we are enjoying beautiful weather here in Havana, I am getting ready to re-install a slightly modified version of the 6 to 18 megaHertz FAN DIPOLE, this one is a little shorter than the standard model, due to the fact that the two supporting towers are a little bit too close to each other. Anyway, the antenna should perform well, something I expect to verify when it is up… By the way the latest analysis of solar activity by experts is telling us that we will again have to deal with an extended period of extremely low solar activity and absolutely quiet geomagnetic conditions…
Now, let´s move on to the second broadband antenna, that is perhaps better known and more popular among short wave listeners and professional HF communications systems, the TTFD or Tilted Terminated Folded Dipole , so well researched by L.B. Cebik, who is offering at his website a treasure chest of antenna related information… the URL is www.cebik.com, again slowly and in phonetics… Charlie, Echo, Bravo, India, Kilo, symbol for period, Charlie Oscar Mike…. Look for the information about the TTFD antenna, and you will find some very interesting comparisons between different lengths of these unique broadband antennas . The TTFD, as I have said here many times, is a compromise antenna system, a good choice if you can only install a single antenna and want to cover a wide frequency range.
For example, a 15 meters long TTFD will be a good choice if you want to monitor the HF bands from 6 to 30 megaHertz , and it will work quite well, with the help of a simple antenna tuner, for transmitting between the seven megaHertz or 40 meters amateur band and 29.7 the top end of the 10 meters ham band.
Now, one more important thing to take into consideration… a TTFD antenna that will be used only for receiving , can be made using 2 Watts non inductive resistors , that will have a total value of between 600 and 1000 ohms. After many experiments it was found that for receive only and QRP low power transmission up to 5 Watts , a very good approach is to place two large sized two watt carbon resistors of between 300 and 500 ohms in series to create a new equivalent resistor of between 600 and 1000 ohms. The two resistors can be placed inside a length of heat shrinking plastic tube, and then attached to a good quality insulator that will take the strain from the upper wires of the antenna… If you want to operate the TTFD with transmitters of more than five Watts, my suggestion is to search for high quality high power non inductive resistors in the 50 to 100 Watts power dissipation range…A pair of 50 watt non inductive 300 ohms resistors connected in series, will provide an excellent terminating resistor for transmitter in the 50 to 200 Watts input power, and I want you to know that 300 ohms non inductive resistors are about the easiest to find of this usually hard to find components.
You will also need to homebrew a balanced to unbalanced radio frequency broadband transformer, better known among radio engineers as a BALUN… balanced to unbalanced abbreviated…
The balun for the TTFD antenna needs to be either a 12 to 1 or a 16 to 1, according to experts.But I have achieved good results when using a 9 to 1 balun. As antenna ¨¨guru ¨¨ L.B. Cebik justly affirms, some radio hobby enthusiasts claim that the TTFD picks up less noise than a standard dipole or long wire, something that I fully back, especially in the case of the long wire antennas…The TTFD picks up less local noise than a long wire and a dipole.
I have written a set of step by step instructions on how to make your own TTFD, that can be sent via e-mail as a compact, rather
small attachment, so if you really want to test drive the TTFD antenna system for short wave reception, just send me an e-mail to arnie at rhc dot cu, and I will send you the computer file as a compact e-mail attachment…
………
Si amigos, yes my friends, oui mes amis, this is the weekend edition of Dxers Unlimited and here at the request of several listeners is information about the Radio Rebelde´s short wave broadcasts… Radio Rebelde is now only operating on 5025 kiloHertz with 50 kiloWatts and its Tropical Band high take off angle main lobe antenna. The daily morning and mid day transmissions are no longer on the air. So, again, for your information, Radio Rebelde´s only short wave outlet that is operational at this moment is on the 60 meters Tropical band , on 5025 kiloHertz and this transmitter is on the 24 hours, to provide primary sky wave service to all of the Cuban archipelago…
And another Cuban broadcast related news item, Radio Angulo, the Holguin provincial network is now with two ten kiloWatt transmitters, one on 740 kiloHertz and the other one on the long time 1110 kiloHertz. The new 740 kiloHertz relay of Radio Angulo is also a 24 hours operation and it is located in Sagua de Tanamo, a mountains region of the province, where the use of a lower frequency on the AM band should improve the coverage.
Now here is our next item here at the weekend edition of your favorite radio hobby program. Cuban radio amateurs are now involved in a revival of home construction of ham radio equipment, including receivers, transmitters, transceivers, antennas and station accessories. A national competition will award nice presents to the best entries on each category. Among the most popular entries are the ones focusing on the homebrewing of rigs for the 160 meters band, that are intended mainly for local communications. My own entry into the national event is going to be the DX-160, a simple, easy to build, rugged and reliable 160 meters band CW transmitter that also has a high efficiency screen grid controlled carrier modulator so that it can be used for local AM phone contacts. The original Arnie Coro´s DX-160 dates back to the 1960´s and I made many nice two way CW DX contacts on 160 meters using it… Now after many years of storage, the announcement of the home brewing competition, made me remember about that rig that is at this moment sitting on top of the main workbench undergoing a major overhaul !!!
Homebrewing ham radio equipment is a lot of fun, I can assure you, and all two way contacts made with radios that you have built yourself have a very special significance… it seems like they sound a lot better than expensive commercially built rigs !!!
Try it, and you will certainly agree with me !!!
And now as always at the end of the program here is Arnie Coro´s Dxers Unlimited´s HF plus low band VHF propagation update and forecast… Solar activity is and will continue to be at very low levels as we pass trough the equinox … so, don´t expect much DX, because the ionosphere is in totally flat state…
Hi amigos radioaficionados around the world, and in space at this moment…welcome to the weekend edition of your favorite radio hobby rogram, the one and only covering the more than 83 different ways that yu and I enjoy playing with our radios… From the Canadian AM broadcast and Dxer trying to set a new record of stations heard on a very small ortable radio, to the Cuban newcomer to amateur radio that yesterday visited me to return the 2 meters band MOXON rectangle antenna that I snt to him so that he could go on the air the very same day that he ceived his amateur radio license… Si amigos, yes my friends, you can besure that people do enjoy this hobby a lot, and even when the going gets difficult, like the day our small fishing vessel that was taking us to the CO4 Dx expedition of 1965 ran aground and water started to come into the hull, instead of panicking, we simply used our ham radio equipment to call for help, as at that time we had no VHF Marine radio coverage in that area of the Cuban archipelago.
Radio brings in so many nice moments, that recalling some of them while spending a nice afternoon at our radio club becomes part of our lives… Now let me give you a nice example of how radio has help a lot of persons to live a better life. For people with poor vision or that are totally blind, amateur radio is a great hobby that makes possible for them to meet friends, participate in contests and share with others their ham radio experience… For highly qualified engineers and telecommunications technicians , the radio hobby makes possible to perform some very interesting experiments using the amateur band frequencies… some of those experiments have become classics, like the ones made by a group of retired professional
Radio broadcast engineers that fully documented the dramatic improvement in performance for vertical antenna systems provided by elevated radials… Amateur radio operators have even made some very important discoveries in the area of radio wave propagation, and experiments that were done by amateurs demonstrated the existence of what we now know as Trans Equatorial Scatter Ionospheric Propagation, or just TEP for short, a fascinating communications mode that so far has defied theoreticians …
Here is now one of the most popular sections of the program… The antenna topics segment, that today will be devoted to part II of low cost broadband antenna systems. During the mid week edition of the show, I gave a lot of information about the FAN DIPOLE, and of its three most popular versions, the one designed for coverage of the 3 to 10 megaHertz part of the short wave spectrum, the one for 6 to 18 megaHertz, certainly the most popular design according to your e-mail messages and letters, and the small compact FAN DIPOLE that works nicely from approximately 13 to 39 megaHertz. At the present moment, and as we are enjoying beautiful weather here in Havana, I am getting ready to re-install a slightly modified version of the 6 to 18 megaHertz FAN DIPOLE, this one is a little shorter than the standard model, due to the fact that the two supporting towers are a little bit too close to each other. Anyway, the antenna should perform well, something I expect to verify when it is up… By the way the latest analysis of solar activity by experts is telling us that we will again have to deal with an extended period of extremely low solar activity and absolutely quiet geomagnetic conditions…
Now, let´s move on to the second broadband antenna, that is perhaps better known and more popular among short wave listeners and professional HF communications systems, the TTFD or Tilted Terminated Folded Dipole , so well researched by L.B. Cebik, who is offering at his website a treasure chest of antenna related information… the URL is www.cebik.com
For example, a 15 meters long TTFD will be a good choice if you want to monitor the HF bands from 6 to 30 megaHertz , and it will work quite well, with the help of a simple antenna tuner, for transmitting between the seven megaHertz or 40 meters amateur band and 29.7 the top end of the 10 meters ham band.
Now, one more important thing to take into consideration… a TTFD antenna that will be used only for receiving , can be made using 2 Watts non inductive resistors , that will have a total value of between 600 and 1000 ohms. After many experiments it was found that for receive only and QRP low power transmission up to 5 Watts , a very good approach is to place two large sized two watt carbon resistors of between 300 and 500 ohms in series to create a new equivalent resistor of between 600 and 1000 ohms. The two resistors can be placed inside a length of heat shrinking plastic tube, and then attached to a good quality insulator that will take the strain from the upper wires of the antenna… If you want to operate the TTFD with transmitters of more than five Watts, my suggestion is to search for high quality high power non inductive resistors in the 50 to 100 Watts power dissipation range…A pair of 50 watt non inductive 300 ohms resistors connected in series, will provide an excellent terminating resistor for transmitter in the 50 to 200 Watts input power, and I want you to know that 300 ohms non inductive resistors are about the easiest to find of this usually hard to find components.
You will also need to homebrew a balanced to unbalanced radio frequency broadband transformer, better known among radio engineers as a BALUN… balanced to unbalanced abbreviated…
The balun for the TTFD antenna needs to be either a 12 to 1 or a 16 to 1, according to experts.But I have achieved good results when using a 9 to 1 balun. As antenna ¨¨guru ¨¨ L.B. Cebik justly affirms, some radio hobby enthusiasts claim that the TTFD picks up less noise than a standard dipole or long wire, something that I fully back, especially in the case of the long wire antennas…The TTFD picks up less local noise than a long wire and a dipole.
I have written a set of step by step instructions on how to make your own TTFD, that can be sent via e-mail as a compact, rather
small attachment, so if you really want to test drive the TTFD antenna system for short wave reception, just send me an e-mail to arnie at rhc dot cu, and I will send you the computer file as a compact e-mail attachment…
………
Si amigos, yes my friends, oui mes amis, this is the weekend edition of Dxers Unlimited and here at the request of several listeners is information about the Radio Rebelde´s short wave broadcasts… Radio Rebelde is now only operating on 5025 kiloHertz with 50 kiloWatts and its Tropical Band high take off angle main lobe antenna. The daily morning and mid day transmissions are no longer on the air. So, again, for your information, Radio Rebelde´s only short wave outlet that is operational at this moment is on the 60 meters Tropical band , on 5025 kiloHertz and this transmitter is on the 24 hours, to provide primary sky wave service to all of the Cuban archipelago…
And another Cuban broadcast related news item, Radio Angulo, the Holguin provincial network is now with two ten kiloWatt transmitters, one on 740 kiloHertz and the other one on the long time 1110 kiloHertz. The new 740 kiloHertz relay of Radio Angulo is also a 24 hours operation and it is located in Sagua de Tanamo, a mountains region of the province, where the use of a lower frequency on the AM band should improve the coverage.
Now here is our next item here at the weekend edition of your favorite radio hobby program. Cuban radio amateurs are now involved in a revival of home construction of ham radio equipment, including receivers, transmitters, transceivers, antennas and station accessories. A national competition will award nice presents to the best entries on each category. Among the most popular entries are the ones focusing on the homebrewing of rigs for the 160 meters band, that are intended mainly for local communications. My own entry into the national event is going to be the DX-160, a simple, easy to build, rugged and reliable 160 meters band CW transmitter that also has a high efficiency screen grid controlled carrier modulator so that it can be used for local AM phone contacts. The original Arnie Coro´s DX-160 dates back to the 1960´s and I made many nice two way CW DX contacts on 160 meters using it… Now after many years of storage, the announcement of the home brewing competition, made me remember about that rig that is at this moment sitting on top of the main workbench undergoing a major overhaul !!!
Homebrewing ham radio equipment is a lot of fun, I can assure you, and all two way contacts made with radios that you have built yourself have a very special significance… it seems like they sound a lot better than expensive commercially built rigs !!!
Try it, and you will certainly agree with me !!!
And now as always at the end of the program here is Arnie Coro´s Dxers Unlimited´s HF plus low band VHF propagation update and forecast… Solar activity is and will continue to be at very low levels as we pass trough the equinox … so, don´t expect much DX, because the ionosphere is in totally flat state…
We may have short openings on 12 and 10 meters, and that´s about all for higher bands DX… while at the same time, local noise levels continue to increase as the summer thunderstorm season approaches… See you all at the mid week edition of the show, Tuesday and Wednesday UTC days , and don´t forget to send your signal reports, comments about the program and radio hobby related questions to arnie at rhc dot cu, or VIA AIR MAIL to Arnie Coro, Radio Havana Cuba, Havana, Cuba
